Thanks to a big first inning and a crucial sixth inning error, Puerto Rico is on their way to the World Baseball Classic semi-finals. They earned a thrilling 6-5 win over USA at Petco Park in San Diego on Friday night. Puerto Rico joins Japan and the ...

Thanks to a big first inning and a crucial sixth inning error, Puerto Rico is on their way to the World Baseball Classic semi-finals. They earned a thrilling 6-5 win over USA at Petco Park in San Diego on Friday night. Puerto Rico joins Japan and the Netherlands in the semi-finals, which is WBCâ€™s version of the final four. Puerto Rico opened Fridayâ€™s game with six consecutive base hits against Marcus Stroman , which, when paired with a sac fly, gave them an early 4-0 lead. USA chipped away in the middle innings and managed to close the gap to 4-3, but a Nolan Arenado throwing error in the sixth allowed Puerto Rico to plate two huge insurance runs. USA scored two in the ninth but left the tying run at third base. Alas. So far Puerto Rico is a perfect 5-0 during the 2017 WBC. Japan is the only other undefeated team. Theyâ€™re 6-0. Puerto Rico was the runner-up to the Dominican Republic in the 2013 WBC and now theyâ€™ll have another shot at a championship. USA, meanwhile, needs a win Saturday night to advance. A loss sends them home. Here are seven things to know about Puerto Ricoâ€™s win on Friday, and whatâ€™s next for USA.1. The USA rotation finally allowed an earned run.Going into Friday nightâ€™s game, the four USA starters (Stroman,Â Chris Archer ,Â Danny Duffy , Drew Smyly) combined to allow one unearned run in 17 1/3 innings in four WBC games. They struck out 22 and walked zero. USA didnâ€™t have any of their big name starters ( Clayton Kershaw , Max Scherzer , etc.), but the rotation was dominant.Â Then, in the first inning of Fridayâ€™s game against Puerto Rico, Stroman allowed six straight singles to begin the game. Six! Here are the six hits: The six consecutive hits gave Puerto Rico a 3-0 lead before they even made their first out of the game. They scored a fourth run in that first inning on a sacrifice fly. USA was facing a big deficit one inning into the game. 2. The USA hit some balls through the marine layer.Petco Park is not a particularly great place to hit during the summer months. That goes double in March. The marine layer at night is nice and thick, turning would be home runs into cans of corn. The fog rolled in before first pitch: Despite that, Buster Posey was able to crush a ball through the thick air and into the right-center field seats for a solo home run in the fifth inning. That brought USA to within 4-2. Hereâ€™s the video: One inning later, Adam Jones yanked a ball to right field for a solo home run, cutting USAâ€™s deficit to 4-3. Here is that video: Puerto Rico kept the door open for USA with some baserunning miscues. Yadier Molina over-slid third base in the first inning and Carlos Correa got caught in a rundown between third and home in the third inning. Those outs short-circuited potentially big innings. (Or a bigger first inning, in Molinaâ€™s case.) 3. Puerto Rico scored two insurance runs without a hit.Just as USA was mounting a comeback and building some momentum, Arenado threw it away. Quite literally too. His sixth inning throwing error allowed Puerto Rico to score two big insurance runs, insurance runs they would ultimately need. They didnâ€™t even have a hit in the inning. A hit-by-pitch, a walk, a couple stolen bases, and the error did the trick. Here is the error: Arenado got a tricky hop at third base, took a second to compose himself, then short-hopped the throw over to first base. Eric Hosmer couldnâ€™t make the scoop. Rough. That ball should have been the final out of the inning, preserving the 4-3 score and USAâ€™s one-run deficit. Instead, it was 6-3 Puerto Rico. 4. USAâ€™s bullpen has been a bit of a problem.Despite all the big names, USAâ€™s bullpen has now allowed 12 runs in 22 total innings in the WBC. The starters have been great even considering Stromanâ€™s rough first inning Friday. The bullpen? Itâ€™s been a bit of a weakness. USA hasnâ€™t gotten the shutout relief work they expected. It cost them against the Dominican Republic last week and it helped Puerto Rico pull away in this game. Everyone is going to focus on Arenadoâ€™s error and rightfully so, but that inning started with a hit-by-pitch and a walk. Canâ€™t be giving out free baserunners like that in a one-run game. 5. USA left the tying run at third base.To their credit, USA did not go quietly in the ninth inning against Edwin Diaz . They were down 6-3 when the first two runners reached base, giving Posey and Paul Goldschmidt a chance to bat representing the tying run. Diaz struck them both out. Posey with a slider and Goldschmidt with a fastball. Itâ€™s not often you see those guys get overpowered like that. Brandon Crawford followed with a two-strike triple to left field to score two runs and bring USA to within 6-5. Replays showed Crawford was indeed tagged out before reaching third base, but he was called safe, and there are no managerâ€™s challenge replays in the first two rounds of the WBC. Puerto Rico couldnâ€™t do anything about it.Diaz bounced back to strike out Josh Harrison , ending the game and stranding Crawford at third base as the tying run. A boring finish this was not.6. Venezuela has been eliminated.Fridayâ€™s game was an elimination game, but not for USA or Puerto Rico. Puerto Ricoâ€™s win officially eliminated Venezuela from the WBC. They are 0-2 in Pool F, and their only chance to advance to the semi-finals involved a three-team tie with 1-2 records. Puerto Ricoâ€™s win improved their Pool F record to 2-0, and since USA and the Dominican Republic play Saturday, one of those two teams is guaranteed to go 2-1. The three-way 1-2 tie is no longer possible. So long, Venezuela. 7. USA will play the Dominican Republic for all the marbles.Ready for some drama? Saturday nightâ€™s game between USA and the Dominican Republic is a winner-take-all game. The winner advances to the semi-finals with Puerto Rico, Japan, and the Netherlands while the loser goes home. The afternoon game between Puerto Rico and Venezuela means nothing and there are no funky tiebreaker rules to consider. Winner moves on and loser goes home. Boy oh boy, thatâ€™s going to be fun, wonâ€™t it? You can relive all the fun from Friday nightâ€™s game with our live blog. We provided commentary, analysis, videos, and all sorts of other good stuff.